Two U.S. Marines were shot Sunday during a live-fire drill at the Marine Corps Air Ground Combat Center at Twentynine Palms, California, and one remains in serious condition, an official told multiple news outlets.

The Marines suffered small-arms gunshot wounds during a maneuver-under-fire drill.

Both were air-evacuated after the incident, and one Marine was later released from the hospital. The other remains in serious condition.

The Marines are from the 1st Marine Division’s 3rd Battalion, 4th Marines.

“Military training is an inherently dangerous task and the 1st Marine Division takes every precaution to ensure the safety of our training,” a statement from the 1st Marine Division said, Military.com reported. “Our commitment is to ensure that our training is as safe as possible. The training we conduct ensures our readiness to respond to any task we are assigned.”